Hydraulic jack



March 20, 1934. l

l. E. DEARSLEY l nYDRAuLI .mex

Filed Dec. 7.1952

4 Sheets-Sheet 1 March 20, 1934- l. E. DEARsLEY.

HYDRAULI C JACK Filed Dec. 7. 1932 4 Sheets-Sheet 2 March 20, 1934. l.E. DEARSLEY HYDRAULIC VJACK Filed uw. v. 1952 4 Sheets-Sheet 5 March 2o,1934. l, E, DEARSLEY- 1,951,399v

HYDRAULIC JACK Patented Mar. 20, 1934 UNITED STATES PATENT oFFl'cEHYDRAULIC JACK Irwin E. Dearsley, Racine, Wis., assigner to WalkerManufacturing Company, a corporation of Wisconsin l Racine, Wis.,

Application December 7, 1932, Serial No. 646,129

4 Claims. (Cl. 13S-9) when lowered, and a relatively long lift in pro-1vportion to this initial height. The jack is also provided with a doublepump mechanism which acts automatically as the operating handle isreciprocated so that the lifting member of `the jack will -be quicklyelevated into engagement with the load by the combined action of the twopumps, and will then be more slowly elevated by one of the pumps afterthe load has been accepted.

The principal object of this invention is to provide an improved jack ofthe type briefly described hereinabove and disclosed more in detail inthe specications which follow. Another object is to provide an improvedtransportable hydraulic jack having a minimum height when lowered sothat it may be positioned under low loads.

Another object is to provide a jack of this type in which the operatingmechanism is protected by the lifting-arm when lowered.

Another object is to provide an improved twospeed hydraulic pumpmechanism.

Another object is to provide improved means for rendering a high-speedpump ineffective when a predetermined load has been accepted.

Another object is to provide improved means for guiding a ram andlimiting the outward movement thereof.

VAnother object is to provide an improved operating handle mechanism foractuating the pumps and controlling the release valve.

Other objects and advantages of this invention will be more apparentfrom the following detailed description of one approved form ofapparatus constructed and operating according to the principles of thisinvention.

In the accompanying drawings:

Fig. 1 is a side elevation of the jack in lowered position, anintermediate portion ofthe operating handle being broken away.

Fig. 2 is a plan view on a larger scale of the operating handle,partially broken away.

Fig. 3 is an enlarged plan view of the jack, with the handle brokenaway, and some portions of the superstructure broken away to discloseunderlying members. V

Fig. 4 is an inside elevation of one of the side frame members with itssupporting rollers.

Fig. 5 is a vertical Vlongitudinal section, taken just inside the framemember 1 and looking toward the opposite side of the jack. v

Fig. 6 is a partial longitudinal vertical section, taken substantiallyon the line 6-6 of Fig. 3.

Fig. 'I is a transverse vertical section taken substantially on the line7-7 of Fig. 6.

Fig. 8 is a partial longitudinal vertical section taken substantially onthe line 8-8 of Fig. 7.

Fig. 9 is a similar vertical section taken substantially on the line 9-9of Fig. '7.

Fig. 10 is a partial transverse vertical section taken substantially onthe line 10--10 of Fig. 6.

Fig. 11 is a transverse vertical section taken substantiallyon the line11-11 of Fig. 6.

Fig. 12 is a detail vertical sectiontaken substantially on' the line12-12 of Fig. 1.

The carriage comprises a pair of similar side frame members l and 2,each of which has a maximum height adjacent its rear vend 3 and tapersdownwardly toward `its front end 4. The forward ends 4 of the sideframes are provided with hubs 5 which are pinned at 6 on a transverseshaft 7 which supports the frame members and spaces them apart. Rollers8 are mounted on the projecting end portions of shaft 7 and held inplace by cotter pins 9. A pump-,block or casting 10 is rigidly securedbetween the rear portions of the side frames 1 and 2 by a bolt 12extending transversely through the upper rear portion of the block andside frames with nuts 12 screwed on its projecting ends, and screw bolts13 projecting through the side frames and screwed into the lower portionof the casting. The upper and forward portions of the block 10, have alateral thickness considerably less than the width of the space betweenthe side frames 1 and 2, so that spaces remain between the block4 andthe side frames to receivey the lifting levers and links, as hereinafterdescribed. A vslip shaft 11 extends through the lower rear portions ofthe block 10 andthe side frames 1 and 2, and rollers 11' are mounted onthe projecting end portions of this shaft and held in place bycotter-pins 11". A ram-cylinder 14 inthe form of an open ended. sleeveis rigidly supported from block 10 by having its rear end exteriorlythreaded and screwed into the block, as indicated at 15. The cylinder 14projects forwardly from the pump block sub-J stantially horizontally, ormay be inclined downwardly at aslight angle, as shown in Fig. 6. Anannular head 16 is screwed at 17 onto the outer end portion of cylinder14- and serves to clamp in place a' larger hollow sleeve 18 whichsurrounds the ram cylinder 14 and ts at its ends cent these side frames.

into recesses provided therefor in block 10 and head 16, respectively.The annular space between the sleeves 14 and 18 serves as a reservoir 19for the oil or other liquid used as an operating `medium in thecylinders. A screw-plug 20 mounted in the top` of sleeve 18 normallycloses an opening through which the supply of oil may be replenished. Anair-vent 21 formed in plug 20 is closed by a screw plug 22 when the jackis shipped, this plug 22 being removed when the jack is in service. Aram 23 is slidable through a packing 24 positioned in head 16 at the endof cylinder 14Vand held in place by a gland 25 screwed into the end ofhead 16. A suitable piston'26 of well known type is mounted at the innerend of ram 23 to maintain a liquid tight fit with the interior ofcylinder 14.4 The forward end of ram 23 is split or recessed to form ayoke, the side arms 27 of which embrace a cross-head 28 tol whichthearms are pinned or riveted at 29. Rollers 30 are pivotally mounted onthe reduced end portions 31 of the cross-head, these rollers 30operating in the guide-ways or channels 32 formed in the inner faces ofthe respective side frames 1 and 2. Stop ribs 33 are formed on the sideframes adjacent the forward ends of these guide-ways for a. purposehereinafter described.

The load-lifting bell crank 34`is in the form of an inverted channelmember having a width approximately equal to the width of the spacebetween the side frames 1 and 2 and having' its side anges 35 extendingdownwardly adja- The bell crank is fulcrumed adjacent its rear upper endon the pivot pin 36 extending transversely through the highest portionof the side frames and locked in place by the nuts 37 screwed on itsthreaded end pcrtions. A pair of similar links 38 are pivot-ed at theirforward ends on the cross head 28 and are pivotally secured by pins 39to the respective downwardly and rearwardly extending end por'-,

tions 40 of the side anges 35 of bell crank 34. The forwardly projecting'ears 40 at the front end of bell crank 34 are pivotally connected bypin 41 at the outer sides of downwardly projecting ears 42 on the loadlifting head 43. It will now be seen that the side flanges 35 of channelmember 34 virtually form a pair of bell-cranks connected togetherv tooperate in unison'by. the top web 50 of the channel, each bell-crankcom.- prising a short arm projecting downwardly between the pump-blockand the adjacent sidevfraV me, and a long forwardly projecting liftingarm. The load-supporting head 43 is provided with a plurality ofupwardly projecting fingers 44 adapted to engage the load, and is formedwitha central opening 45 vwhich may receive .a downwardly projectingportion of thev load. A pair of similar parallel-motion links 46 arepivoted at their front ends on pin 47 between the ears 42 oftheload-supporting head and are pivoted at their rear ends cna pin 48extending horizontally through a boss 49 formed on the upper frontportion of pump block 10. The distance between pivotal axes 36 and 48 issubstanj tially the same as that between axes 4l and 47,

and the links 46 are of substantially the same length as the portion ofbell crank 34 between the axes 41 vand 36 so that the links 46 and lever34 will swing substantially parallelto one another and theload-supporting head-i3 will remain substantially horizontal at allelevations. It will be noted that all -of the links 38 and 46 are housedbeneath and within the channel.

height. The underlying members are also protected by the top plate orweb 50 of the channel member 34 so that the jack will have a neat andpleasing appearance and be substantiallyv enclosed when in loweredposition, as shown in Fig. 1. The cover plate 5 0 will also serve toprotect the underlying parts in case the loador any vother object shouldfall upon the jack.

The forward end portions of links 38 engage the stop ribs 33 to limitthe upward movement of the load-lifting members and the vforwardmovement of the ram.

When oil or other liquid is forced into the ram cylinder 14 (in themanner hereinafter described), the ram 23 will be projected forwardly,thereby pulling the links 38 forwardly and swinging the bell crank 34 upto the position shown in solid lines in Fig. 5. 4When the oil ispermitted to flow out of ram cylinder 14, the p arts will be returned tothe position shown in dotted lines f in Fig. 5, and in solid lines inthe other figures of the drawings, by the load resting on head 43 andthe weight of the elevated parts. To insure the complete lowering of thejack after the load has been disengaged, retraction springs 51 aresecured at their forward ends 52-to the cross head 28 and at their rearends 53 to the respective side frames 1- and 2 adjacent the anchoringbolts 13. These springs will be extended when the load is elevated andwill serve to return all of the parts to the lowered position eventhough there is no load on the supporting head 43.

A pair of similar substantially horizontal pump cylinders 54 and 55extend inwardly thro-ugh the rear end of block or casting 10. Thecylinders are of similar length but cylinder 54 is of considerablylarger diameter than cylinder 55. A piston 56 is slidable in cylinder 54through a packing 57-held in place in the outer end of the cylinder bymeans of glandV 58. A suitable cuppacking 59 is secured on the inner endof piston 56 to form a iluid tight joint between the inner end of thepiston and the walls ofthe cylinder. An exactly similar piston assembly60, but of smaller diameter, is mounted in the other pump cylinder 55.

The operating handle comprises a hollow casting 61 fulcrumed on pivotpin 62 mounted in the rearwardly projecting ears 63 at the rear ends ofside frames 1 and 2. A downwardly projecting short arm or crankextension 64 formed on casting 61 carries a cross pin 65 which v6.8 and69 which are secured at their rear ends to the opposite sides of thecasting 61 by transversely extending pins or rivets 70. The bars 68 and69 converge rearwardly and are secured at their rear ends by bolts 71and 72 to the opposite sides of the forward end of a fiat bar 73. A pairof similar semi-cylindrical wooden handgrip members 74 having roundedend portions are secured to the opposite sides of the free rear endportion of bar 73 by means of screws 75. An upright bracket member 76 iscentrally looped to enclose the three bar members 68, 69 and 73, beingsecured thereto by the bolt 72 (see Fig. 12). The bracket 76 comprisesadownwardly projecting leg or rest 77 which is adapted to support thehandle in its extreme lowered position,

as shown in Fig. 1. An upwardly projecting boss 78 formed on the top ofbracket 76 is perforated to form a bearing 79 for the rotatableoperating rod or shaft 80, hereinafter described. The casting 61isfprovided with an upwardly and forwardly projecting lip portion 81adapted to engage an upper portion of block 10 to limit the upwardswinging movement of the handle. This also provides a means whereby therear portion of the carriage may be lifted from the ground by means ofthe handle so as to facilitate maneuvering the jack.

A longitudinally extending oil passage 82 formed in the lower portion ofpump casting 10 communicates at its forward end with the reservoir 19,and conmiunicates intermediate its ends with a transverse conduit 83. Apassage 84 extends downwardly through the .upper portion of casting 10in front of pump cylinder 54, this passage being closed at its upper endby screw plug 85. A lateral passage 86 leads from passage 84 into theram cylinder 14. Aball Valve 87 engages a valve seat 88 formed at thelower end of passage 84, the ball being normally held against its seatby the spring 89 confined between the ball and the screw plug 85. Asmaller passage 90 extends downwardly below valve seat 88 andcommunicates through lateral passage 91 with the pump cylinder 54. Thelower end of passage 90 communicates with the transverse passage 83,already described, and a ball valve 92' is normally held against seat 93at the lower end of passage 90 by means of spring 94 confined betweenthe two balls 93 and 87. An exactly similar set of valved passagesconnects the other pump cylinder with the supply conduit 83 and the ramcylinder 14, all as shown in Fig. 9.

On the rearward or suction stroke of either one of the pump pistons, thevalve 92 will be lifted and oil will be drawn from the reservoir throughpassages 82, 83, 90 and 91 into the pump cylinder 54 or 55. On theforward stroke of the piston, valve -92 will close and Valve 87 willopen to permit this oil to be forced from the pump cylinder throughpassages 91, 90, 84 and 86 into the ram cylinder.

A discharge passage 95 leadsrearwardly from ram cylinder 14 andcommunicates with a vertical passage 96 which leads down into transverseAconduit 83. The discharge passage 95 is normally closed by alongitudinally movable Valve 97 carried at the forward end of a valverod 98 slidable in the passage 99 formed in block 10. A rotatablevalve-operating rod 100 engages the reciprocable valve rod 98 at itsforward end, and is threaded at its rear portion 101 to screw into acorrespondingly theaded opening in the annular plug 102 which is screwedinto block 10 against a packing 103. A universal joint 104 connects therear end of rotatable valve-operating rod 100 with the forward en d ofthe rotatable valve-operating shaft already described. This shaft 80extends rearwardly vand upwardly through the operating handle and isrotatably and slidably supported adjacent its rear end in the boss 78 ofbracket 76, as already described.

Shaft 80 is provided on its rear end with a laterally extendingoperating crank orv handle 105 which will be in the position shown inFigs. 1, 2 and 12 when the valve 97 is closed. This will be the positionof the parts when the jack is being permit the valve 97l to be forced.away from its valve seat, thus permitting a restricted ow of l oil fromthe ram cylinder 14 through passages 95, 96, 83 and 82 back into thereservoir 19. This lowering movement may be stopped at any time orsuitablyrestricted by the proper manipulation of handle 105 and valve97.

A by-pass passage 1 06 leads from the forward end portion of cylinder 54into the central horizontal discharge passage 82, (see Fig. 7). A ballValve 107 is 'normally held against a valve seat 108 at the dischargeend of by-pass 106 so `ras to prevent the flow of oil through thispassage. Ball valve 107 is normally held closed bythe spring 109confined between follower 110, slidable in passage 111 and an adjustablescrew plug 112 threaded in the outer portion of passage 111. The exposedend' of passage 111 is normally closed by disc orplug 113. By adjustingthe screw plug 112 in or out, the compression of spring 109 may beadjusted so as to determine the pressure at which ball valve 107 willopen. Inv

an exactly similarmanner, a by-pass 114, 115 extends from the inner endportion of pump cylinder 55 to the discharge passage 82, (see Figs. 9andy 10.) This by-pass is normally closed by the safety ball valve 116held in pla/ce by adjustable spring 117 in the same manner as valve1.07,

already described. Valve 107 is adjusted to open at a much lowerpressure than valve 116, as will be hereinafter apparent.

During the initial elevating operation, before they load is encountered,both pumps will operate simultaneously to force oil from the reservoir19 into the ram cylinder 14, and since pump 55 is of considerablecapacity, the lifting arm 34 will be very rapidly elevated until theload is engaged. After the load is engaged by the l'fting head 43 (ifthis load is of considerable weight), the consequent resistance to the-j'forcing of liquid into the ram cylinder 14 will be greater than thepressure for which the ball valve 107 is adjusted so that thisvalve-will open during thevoperative stroke of piston 56 and the oildrawn into the larger pump cylinder 54 will be discharged throughby-pass 106 back into/#the reservoir. In other words, the largerorrhigh-speed pump will be ineffective as soon as a certainpredetermined maximum load is imposed on theram and lifting mechanism.However, the ball valve 116 controlling the by-pass from the smaller orlowspeed pump 55 is adjusted so as to normally remain closed so long asthe load on the jack is noty in excess of the safe load to be handledthereby. Accordingly, the smaller pump 55 will continue to operate toforce liquid into the-ram cylinder 14 and elevate the load. Pump 55 isso designed that the load may be elevated without applying excessiveforce to the operating handle. be seen that the operating handle may beoscillated continuously -and the lifting head 43 will be elevatedrapidly until the load is engaged and controlling the'by-pass from pump55 is merely a safety valve and remains closed at all times unless anexcessive load is imposed on the jack or- It will thus attempt is madeto operate the pump after the jack has been completely elevated. At suchtimes the valve 116 will open to permit oil to flow directly fromcylinder 55 back to the reservoir without causing injury to theoperating mechanism.

'When' the jack is to be lowered, this is accomplished by swinging overthe handle 105 of rotatable shaft .80 to open the valve 97, in themanner already described. The retraction springs 51 insure a completelowering of the jack after valve 97 has been opened, even though thereis no load on the jack.

universal joint 104 is not located directly on the pivotal axis of theoperating handle, there will be a slight longitudinal movement of.valve-operating shaft through bearing 79 as the operating handle isoscillated. 'I'his will have no effect on the release-valve 97 sincethis valve can only be operated by a rotary movement of the operatingshaft.

It will now be seen that this jack is extremely compact, and easy tomaneuver into position under Very low loads; A two-speed operatingmechanism is provided which operates entirely automatically so that` bymerely oscillating the operating handle the jack will be quicklyelevated into engagement with the load, and the yload will then beraised at a much slower` rate so that a heavy load may be handled easilyand safely without undue exertion. a l

I claim:

1. In a hydraulic jack, a carriage `comprising longitudinal side frames,a horizontally positioned pump-block rigidly connected between thevrearlower portions of the side frames, a ram cylinder projectingforwardly from the pump block, a ram slidable in the cylinder, a liftingbell-crank in the form of an inverted channel, the bell-crankbeing sfulcrumed between the upper portions of the side frames above thevpump-block with the side flanges of the channel projecting downwardlyadjacent to and between the side frames and at the sides of the block,

a lifting head at the free end vof the bell-crank,v

bell-crankin the form of an inverted channel,

the bell-crank being fulcrumed between the upper portions of the sideframes above the pump-block with the side flanges of the channelprojecting downwardly adjacent to and between the side frames and at thesides of the block, a lifting head pivotally mounted at the free end Itwill be noted that due to the fact that the .of the bell-crank, linksconnecting the ram with the lower portions of the side flanges of thechannel between the side frames and the block, and parallel motion linkspivoted at theirforward ends to the head and at their rear ends to thepump-block and housed within and beneath the channel when the bell-crankis lowered.

3. In a hydraulic jack, a carriage comprising.'

longitudinal side frames, a horizontally positioned pump-block rigidlyconnected between .the rear lower portions of the side frames, a ram.cylinder projecting forwardly from the pump of the bell-crank, linksconnecting the ram with',

the lower portions of the side flanges of the channel between the sideframes and the block, and v parallel motion links pivoted at theirforward ends to the head and at their rear ends to the pump-block, bothsets of links being housed Within and beneath the channel when thebell-crank is lowered.

4. In a hydraulic jack, a carriage comprising longitudinal side frames,a horizontally positioned pump-block rigidly connected between the rearlower portions of the sideframes, aram cylinder projecting forwardlyfrom the pumpblock, a ram slidable in the cylinder, a cross-headconnected with the forward end of the ram, there being channeledguide-Ways formed in the inner faces of the side frames for receivingthe ends of the cross-head, a lifting bell-crank in the form of aninverted channel fulcrumed between the upper portions of the side framesabove the pump-block with the side flanges of the Vchannel projectingdownwardly adjacent to and between the side frames and at the sides ofthe block, a lifting head at the free end of the bell-crank,

links connecting.the cross-head with the lower l12( portions of the sideflanges of thechannel, stops formed on the side frames adjacent theforward ends of the guideways and engaged by the links

